What can a runner with knee pain do at the gym?

Some gym training options and considerations for runners (and others) with overuse injuries of the knee

I am a science writer, the Assistant Editor of ScienceBasedMedicine.org, and a former Registered Massage Therapist with a decade of experience treating tough pain cases. I’ve written hundreds of articles and several books, and I’m known for sassy, skeptical, referenced analysis and a huge bibliography. I am a runner and ultimate player, and live in beautiful Vancouver, Canada. • full bio • about PainScience.com

I have often emphasized the under-rated importance of resting in rehabilitation: there’s more to it than it seems, and it is rarely given the respect and appreciation it deserves. Taking the strain off vulnerable tissues is the foundation of recovery from many of the world's most common and frustrating injuries. Doing it intelligently, in a way that protects and preserves your fitness at the same time, is a good challenge.

Warning! This is no mere “gym tips” article! This goes much deeper down the rabbit hole of rehab reasoning than a few gym tips for injured runners. For instance, note that I close with an example of a patient who has little interest in gyms, an older woman who just wants her daily walks back. As you read on, notice the delving into tactics. The goal here is not just to know what to do at the gym, but to get rather clever and serious about the way you “troubleshoot” any injury. Few people have really thought this stuff through. When I say — and I often do — that almost no patient has actually “tried everything,” this is the kind of thing I mean.

Having made that point at length, I'd now like to give some specific examples of relative rest strategies for two of those injuries: the runner's knee injuries, iliotibial band syndrome and patellofemoral syndrome. I have written a beefy tutorial about each of these injuries, and have corresponded extensively — thousands of emails — with patients around the world. One of the most common themes in those discussions is that runners want to know:

So what can I do instead of running?

They have the (good) impulse to use “relative rest”: to rest their knees while remaining as active as possible otherwise, to work around their pain instead of working through it. But folks are often surprisingly unsure how to go about this, to the point where I decided it was time to do some writing about it.

It “should” be relatively obvious: do anything at all, as long as it doesn’t piss off your knees! But there is clearly an emotional element to the challenge that makes sensible and creative planning difficult. Runners want to run and non-running options do not compute. As I have pointed out so often, in so many ways, injured runners’ are generally their own worst enemy.

Today we’ll take a close look at strength training around knee pain. Most runners are wondering about strength training of the leg in particular, because they want to keep their legs in shape. This is a good idea. Strength training is quite a beneficial form of exercise in general, and more efficient than most people realize.

Strength training around patellofemoral pain syndrome

The leg press machine is one of the most popular in the gym. It is completely off-limits for patients with patellofemoral pain.

My advice is the polar opposite of the conventional wisdom on this point, and has been for many years now. PFPS patients are usually told to train their quadriceps as a treatment, but I recommend avoiding it until the knee is substantially recovered. This debate is covered thoroughly in my advanced PFPS tutorial. In a nutshell, I have yet to see persuasive evidence that vastus medialis strength actually actually works for PFPS. Meanwhile, there is an obvious reason why it might actually do harm. Until it is proven safe and effective, I will continue to exercise the precautionary principle and warn people away from quadriceps training as a PFPS treatment.

So what is the risk of harm? Any strong knee straightening — heavily loaded knee extension — impressively increases pressure between the kneecap and the femur, and therefore is potentially a major risk factor. Therefore, the PFPS patient must, in my opinion, completely avoid the two most classic thigh strength training exercise until quite recovered:

the leg press machine

any kind of squat, deep knee bend

That’s unfortunate, because those exercises are favourites for a reason: they use huge muscle groups, the so-called “anti-gravity” muscles, the quadriceps, hamstrings and gluteals, and using them intensely is a great workout. However, they are simply off limits until PFPS knees are mostly recovered.

Fortunately, virtually anything else is perfectly fair game … even other exercises that use the knees.

For instance, a good replacement is to work the large hamstring muscle group with a hamstring curl machine. This is a much less popular piece of gym equipment for some reason, but it’s certainly useful here. When you squat or leg press, the powerful hamstrings are involved and the patellofemoral joint is squeezed mightily. But a hamstring curl contracts the hamstrings without significant strain on the patellofemoral joint — it’s like magic.

What’s the difference? Knee action can be powered from either side of the joint. The quadriceps pull one way from one side, and the hamstrings pull the other way from the other side. The quadriceps pull on the front of the tibia (the big lower leg bone), while the hamstrings pull on the back. The quadriceps are more powerful, and have better leverage — the actual biomechanical purpose of the kneecap. But the hamstrings are also extremely strong … and they can’t move the knee without cinching up that patellofemoral joint either.

In a squat or leg press, it’s all going on: both groups are working in concert to powerfully extend and to control flexion. But the hamstring curl eliminates the quadriceps from the equation, forcing all knee movement to be powered by the hamstrings alone — a less powerful movement, but still a big muscle group hard at work.

Certainly the knee is still bending and therefore the patellofemoral joint is compressing, as it always does with any flexion past a few degrees, loaded or unloaded, and so patients with severe PFPS may want to avoid this too: but it is a much less stressful exercise for the patellofemoral joint than the squat or leg press. This makes it a fine compromise exercise for many people. The hamstrings have a lot of mass, and you can build a lot of fitness by strengthening them, just as you can by training the quadriceps.

There is a popular notion that it is important to use the full range of movement when strength training. There is undoubtedly a case to be made for it, but it’s an exaggeration to call it “important” — contraction is contraction is contraction, and a heavily loaded 60˚ movement is going to challenge in the muscle metabolically in pretty much exactly the same way as a 120˚ arc. So do 60˚ instead of 120˚ to get virtually identical training benefit with about half the knee flexion risk.

There is still some strain on the patellofemoral joint in a hamstring curl, so we can refine the exercise a little more to make it a bit safer: just limit the degrees of flexion. Don’t bend the knee as far. Every degree of flexion increases the pressure in that joint, but you don’t have to use all of the degrees available. Curl half way! Curl 60˚ instead of 120˚!

Strength training around iliotibial band syndrome

ITBS is all about repetitive movement, so any repeated knee flexion at all is a risk, regardless of what kind of knee flexion. Every single swing of the knee is potentially a problem. It’s a numbers game.

Not all flexion is created equal, and the risk varies with different exercises. For instance, it’s clear that cycling is generally less irritating to ITBS than running, even though it is just as repetitive. But it is by no means risk free, and some ITBS patients have just as much difficulty with cycling as they do with running. At the other extreme, the biomechanics of climbing down a mountain are especially bad for ITBS (for no super-clear reason — but that’s the way it is).

To truly rest an ITBS knee, then, you simply have to limit the number of swings of that hinge.

Strength training at the gym may be quite a good choice, though, because it is possible to strength train with minimal repetitions. In fact, strength training is offers the best trade-off between maximum benefit for a minimum number of repetitions. By definition, strength training involves just a few intense contractions: “high load” but “low reps” (repetitions). The goal is to quickly exhaust muscle fibres, in just 10-20 repetitions, or a couple of minutes. The knee joint is under a lot of strain … but not from repetition.

A dozen knee bends is an extremely small number compared to what it will be subjected to in even the shortest run!

Better still, repetitions can be minimized even further with the slow contractions favoured by some experts. For instance, Doug McGuff, author of Body by Science, advocates this and teaches readers to focus on time under load — a couple minutes — rather than on repetitions. In other words, five super-slow repetitions spread out over a couple minutes may be even better than 15 repetitions, or the equal of it. This is debated ad infinitum by the bodybuilding experts, but it doesn’t really matter for our purposes: super-slow contractions may or may not be the absolute best training style, but who cares as long as it works reasonably well and limits repetitions? It’s just gravy if it also happens to be the bestest of all methods! Which it might conceivably be …

The heavy loading might still be a problem for some people. But test it: what happens when you do a set of leg presses or squats? How irritating is it compared to a run?

Two examples of rehab compromises

The creative challenge of resting always involves trade-offs and compromises. Short of living in a wheelchair, it is literally impossible to avoid all knee irritation. Strength training the legs is a way of continuing to exercise your legs while minimizing — not eliminating — the risks to an injured knee.

This may be an extremely useful strategy for many patients … and not at all for others. Here are two contrasting examples, Young Running Man and Old Walking Lady:

Younger Running Man. YRM is an serious amateur athlete with IT band syndrome, preparing for a career move: officer’s training school (OTS), which has some serious minimum fitness requirements. They are easy enough to meet for a reasonably athletic person, but tricky with an injury. He starts in about four months. The stakes are high, he’s never really encountered any serious setbacks as an athlete before, and he’s understandably reluctant to rest!

This guy is a perfect candidate for strength training his legs: he has a real reason to continue preparing his body for the ordeal ahead, and yet he also badly needs to protect his knees. There’s almost no chance that his knee will actually be fully recovered by the time he gets to OTS, but he can at least get it as calm as possible. He doesn’t have to be pain-free to get through OTS, just pain-free enough! A high-intensity style of strength training for the legs is a good compromise here: good training with a minimal knee movement. He can start OTS with legs in excellent overall condition, and knees as un-irritated as possible.

Older Walking Lady. OWL is a PFPS patient with radically different set of priorities: her main concern is being able to maintain general fitness with a walking habit, which is a great goal … but there’s no career at stake, no deadline, and no challenging physical! Even though she could strength train her legs, there’s really no need for her to risk irritating her knees at all: it probably makes sense to avoid all knee stress entirely for a while. Her general fitness can easily be rebuilt when her knees are ready to get back to walking. But she can and should — if she is at all earnest about her health — also maintain her general fitness by strength trainingother musculature in the body.

Like many older women — perhaps most — she’s not particularly keen on the gym. However, for the sake of her worthy goal, she can cope. Muscle mass drops off sharply later in life, and maintaining it is more than just a good idea: it is almost a necessity. Switching to a fitness programme dominated by strength training for a few months is a small price to pay for maintaining fitness while also allowing complete rehabilitation of the knees. Soon enough, walking will become an option for her again … although by that time she may have discovered that the gym isn’t so bad.

Maybe she’ll even start to enjoy being surrounded by young male bodybuilders at the gym!

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I do go on about rest, don’t I? I do it because resting effectively for rehab is just not as easy or simple as it sounds. All of the above is a demonstration of what I mean by being “creative and precise” with a resting “strategy”: with some savvy planning, you can almost always find ways to get an excellent workout and yet still protect tissues that truly need a break. If I had a buck for every time I’ve seen this “simple” thing done well in cases where the need for it was clear — often desperate — I would have enough about enough money for a cheap lunch.